Technical Abstract:
Ribstone Indian ricegrass (Achnatherum hymenoides [Roem. & Schult.] Barlw.) germplasm (Reg no. , PI 632634) was released 13 Jan. 2003 as a selected class of certified seed (genetically manipulated track). This class of prevariety germplasm is eligible for seed certification under guidelines developed by the Association of Seed Certifying Agencies (2001). Participating in the release are the USDA-ARS, the Utah Agricultural Experiment Station, and Ducks Unlimited-Canada. The intended area of use for Ribstone is on sandy soils of ecoregion #1 (dry mixed grass), characterized by brown chernozem soils (Strong and Leggatt, 1992). This ecoregion occupies an area of southeastern Alberta bordered on the north by about 52degrees 40' N and on the west by about 112degrees 25' W, extending into Saskatchewan and Montana.
Ribstone (experimental designation 0-4) was selected from T-918, a population collected July 27, 1993 by T. A. Jones north of Taber, AB, across the Oldman River from Taber Provincial Park (49degrees 49' 15" N 112degrees 10' 06" W). The soil at the collection site is a non-saline (EC=0.2 mmhos cm-1) slightly alkaline )pH=7.8) sand (96% sand, 2% silt, 2% clay). At the time of collection, this accession was noted as featuring an acute glume pair angle, a trait previously associated with seed retention in the Indian ricegrass cultivar Rimrock (PI 4768833) (Whalley et al., 1990: Jones and Nielson, 1992, Jones et al., 1998). High seed retention facilities improved mechanical seed harvest of Indian ricegrass, a species that exhibits both indeterminate flowering and seed shattering (Jones, 1990). Associated plant species at the site were other native grass species, green needlegrass (Nassella viridula [Trim.] Barkw.), needle-and-thread (Hesperostipa comata [Trin. & Rupr.] Barkw.), blue grama (Bouteloua gracilis [Kunth] Lag. ex Griffiths), western wheatgrass (Pascopyrum smithii [Rydb.] A. Love), thickspike wheatgrass (Elymus lanceolatus [Scribn. & J. G. Smith] Gould), and prairie junegrass (Koeleria cristata Pers.); shrubs Rosa sp. and Symphoricarpos sp.; and forbs Opuntia sp., Cleome sp., and Dalea sp.
T-918 was established at Evans Farm (Millville, UT) in May, 1994 in an evaluation of 10 Indian ricegrass accessions collected in Alberta. T-918 had the highest seed yield in 1995 and 1996 and the third highest and sixth-highest germination following prechill in 1995 and 1996-harvested seed, respectively. Five of the 10 accessions, including T-918, were advanced to a second trial established in April, 1997 at Greenville Farm (North Logan, UT). From this planting, ten of 123 individual T-918 plants were visually selected in 1999 for acute glume pair angle. Their seed was bulked (0-4) and used to establish a G-1 seed increase at Cornish Farm (Cornish, UT) in April, 2000. Pre-chilled germination of 2002 Ribstone germplasm seed produced at Cornish was 66.2%, compared to 33.9% for 'Rimrock'.
Seed of the G-1 generation will be maintained by the USDA-ARS Forage and Range Research Laboratory, Logan, UT, and seed of G-2 and G-3 generations will be made available to growers by Ducks Unlimited-Canada and the Utah Crop Improvement Association. Seed through the G-4 generation will be eligible for certification, but sale of Ribstone seed beyond generation G-4 is expressly prohibited to limit genetic shift. Small quantities of seed will be provided to researchers on request to the corresponding author. Appropriate recognition should be made if this material contributes to the development of a new breeding line or cultivar.